/************************************************************************
 * Copyright (c) 1990, 1993
 *    The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Chris Torek.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 ************************************************************************/


#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)makebuf.c    8.1 (Berkeley) 6/4/93";
#endif /* LIBC_SCCS and not lint */
//#include <sys/cdefs.h>
//__FBSDID("$FreeBSD$");

//#include "namespace.h"
//#include <sys/types.h>
#include "sys/stat.h"
#include "unistd.h"
#include "stdio.h"
#include "stdlib.h"
#include "errno.h"
//#include "un-namespace.h"

//#include "libc_private.h"
#include "local.h"

/*
 * Allocate a file buffer, or switch to unbuffered I/O.
 * Per the ANSI C standard, ALL tty devices default to line buffered.
 *
 * As a side effect, we set __SOPT or __SNPT (en/dis-able fseek
 * optimisation) right after the _fstat() that finds the buffer size.
 */
void
__smakebuf(FILE *fp)
{
    void *p;
    int flags;
    size_t size;
    int couldbetty;

    if (fp->_flags & __SNBF) {
        fp->_bf._base = fp->_p = fp->_nbuf;
        fp->_bf._size = 1;
        return;
    }
    flags = __swhatbuf(fp, &size, &couldbetty);
    p = malloc(size);
    if (p == (void*)NULL) {
        fp->_flags |= __SNBF;
        fp->_bf._base = fp->_p = fp->_nbuf;
        fp->_bf._size = 1;
        errno = ENOMEM;
        return;
    }
    flags |= __SMBF;
    fp->_bf._base = fp->_p = (unsigned char *)p;
    fp->_bf._size = size;
    if (couldbetty && isatty(fp->_file))
        flags |= __SLBF;
    fp->_flags |= flags;
}

/*
 * Internal routine to determine `proper' buffering for a file.
 */
int
__swhatbuf(FILE *fp, size_t *bufsize, int *couldbetty)
{
    struct stat st;
#ifdef LOSCFG_FS_VFS
    if (fp->_file < 0 || fstat(fp->_file, &st) < 0) {
        *couldbetty = 0;
        *bufsize = BUFSIZ;
        errno = EBADF;
        return (__SNPT);
    }
#endif
    /* could be a tty iff it is a character device */
    *couldbetty = (st.st_mode & S_IFMT) == S_IFCHR;
    if (st.st_blksize <= 0) {
        *bufsize = BUFSIZ;
        errno = ENOTBLK;
        return (__SNPT);
    }

    /*
     * Optimise fseek() only if it is a regular file.  (The test for
     * __sseek is mainly paranoia.)  It is safe to set _blksize
     * unconditionally; it will only be used if __SOPT is also set.
     */
    *bufsize = st.st_blksize;
    fp->_blksize = st.st_blksize;
    return ((st.st_mode & S_IFMT) == S_IFREG && fp->_seek == __sseek ?
        __SOPT : __SNPT);
}
